The present invention relates to a jack safety device, and particularly to a jack safety device which may prevent the accident of the object falling down due to the failure of lifting mechanism of the jack.
A hydraulic jack in general has used a hydraulic cylinder as lifting mechanism. If because of breakage or oil leakage on the hydraulic cylinder, the object under holding will fall down swiftly owing to sudden missing of lifting force from the jack and therefore to cause accidental injury.
Further because of space and mechnism limit to a small hydraulic cylinder in general, it has not found a practical safety device so that it gives no protection for use.